August 20, 2008

Broad-faced men are more aggressive

No matter how hard men try, they may not be able to hide their aggression. A study in male ice-hockey players suggests that to gauge a man's aggression levels, you just have to look at the proportions of his face.

Cheryl McCormick and Justin Carre from Brock University in Ontario, Canada, found that the larger the width-to-height ratio of a player’s face, the more aggressive they were.

They measured aggression by the number of penalty points each player accrued for potentially harmful behaviour, such as elbowing and fighting.

In general, men's faces tend to have a larger width-to-height ratio than women's. This physical characteristic has been linked to higher levels of testosterone, which in turn is linked to aggressive behaviour.

consider the man of good nature to be such... raised and fleshy faces, but not narrow

and the Physiognomonica of Adamantius:

το θηλυ ως επι το πολυ εχει του αρρενος ... προσωπον στενωτερον

the female in most cases, compared to the male, has ... a narrower face

A reader asks in the comments whether men are indeed broader-faced than women. Looking at the data of Farkas et al. [International Anthropometric Study ofFacial Morphology in Various Ethnic Groups/Races], it appears that this is not the case. Out of the 25 groups where both male and female data exist, in 19 men have a higher facial index (narrower-faced) than women, and in 6 the opposite is true.

Here are the 6 groups where men have broader faces than women (greater difference first):

The median ratio of men/female F.I. is 101.9% (Slovenians); for Greeks it is 102%, very close to the median. For white Americans, the ratio is 102.3%.

I also looked at Howells' craniometric data, which includes a wider sampling of world populations, taking the ratio of Nasion-Prosthion/Bizygomatic. The ratio of the male to the female average is 99.5%, practically the same.

So, while men do have wider faces in the absolute sense (mean +7.6%, median +3.6% in the Howells set; mean +5.6%, median +6.3% in the Farkas set), they do not appear to have wider faces in terms of proportions compared to women.

[I will comment further when I read the article]

UPDATE (Aug 21)

I have posted the abstract below. They looked at the upper face, not the total face height, thus the data of Farkas et al. (which did not measure upper face height) are not relevant. But, the skull data of Howells is relevant, and do show the predicted sexual dimorphism, although not very noticeable on a global scale.

Young children possess shorter, broader faces relative to those of adults. However, a distinction between the sexes can also be observed that is linked to distinct male and female growth trajectories (Figure 1). Analysis of individual traits against age indicates that male and female growth trajectories diverge at puberty for BZW but not for FHT (Figures S2 and S3). This relationship of width-to-height of the upper face deviates from predictions based on ontogenetic scaling, as males (which are, on average, larger than females) have similar facial heights to females, whereas facial breadth is larger in the male

They used a South African collection to arrive at this conclusion.

I examined ZYB/NPH on either Europeans or Zulu, and list the mean and median values of the trait for men and women:

Europeans

Men

Women

Mean

ZYB/NPH

1.969

1.977

Median

ZYB/NPH

1.971

1.984

Zulu

Men

Women

Mean

ZYB/NPH

1.936

1.943

Median

ZYB/NPH

1.926

1.922

So, these don't look supportive of greater ZYB/NPH in males than in females. In this paper, the authors measured ZYB/NPH from photographs. It is very difficult to get an accurate estimate of the nasion, prosthion or zygomata using a photograph; the authors report high inter-rater reliability, but reliability means that different raters measure similarly, not that they measure correctly!

In particular they measured upper facial height from the brow to the lip. Their photograph indicates that they took this measurement from the lower point of the eyebrows. Since men are both hairier and don't remove eyebrow hair, it is quite possible that women's upper facial height was inflated. In any case, taking the upper facial height from the brow is not consistent with taking the nasion-prosthion height.

So, while the conclusion that broader-faced men are more aggressive is correct, the explanation that it is due to men having a higher breadth/upper face ratio seems suspect.

Proceedings of the Royal Society B doi: 10.1098/rspb.2008.0873

In your face: facial metrics predict aggressive behaviour in the laboratory and in varsity and professional hockey players

Justin M. Carré, Cheryl M. McCormick

Abstract

Facial characteristics are an important basis for judgements about gender, emotion, personality, motivational states and behavioural dispositions. Based on a recent finding of a sexual dimorphism in facial metrics that is independent of body size, we conducted three studies to examine the extent to which individual differences in the facial width-to-height ratio were associated with trait dominance (using a questionnaire) and aggression during a behavioural task and in a naturalistic setting (varsity and professional ice hockey). In study 1, men had a larger facial width-to-height ratio, higher scores of trait dominance, and were more reactively aggressive compared with women. Individual differences in the facial width-to-height ratio predicted reactive aggression in men, but not in women (predicted 15% of variance). In studies 2 (male varsity hockey players) and 3 (male professional hockey players), individual differences in the facial width-to-height ratio were positively related to aggressive behaviour as measured by the number of penalty minutes per game obtained over a season (predicted 29 and 9% of the variance, respectively). Together, these findings suggest that the sexually dimorphic facial width-to-height ratio may be an ‘honest signal’ of propensity for aggressive behaviour.

I think skinny faced men are introvert and deal with just their own,but I don't think they are less aggressive.I've noticed they are agressive about things that interest them,but not about the whole damned world.I think the square headed dudes are less aggressive;you really got to drag them out of their caves.Personally,I think agression is in the mind-If I want something-I gotta go get it or do it-it's not gonna go right by itself;See It's all in the HEAD.(My face is skinny up front and square on the back jaws.

The only strange thing here is that I've always thought it was women who had broader faces (a juvenile trait). How can it not be so?? Surely, you have to admit that at least that's the impression that you get when you look at women with typical feminine hairstyles.

Unless I'm misunderstanding the term broad-faced. Is it talking about looking face-on, or maybe sideways? If it's sideways, then sure, men with bigger jaws look more aggressive and I can see how they might act more aggressive too just based on their own looks.

"Men who are typically more aggressive have more testosterone, which means they are generally more muscular and have a stronger bone structure, often evident in the jaw line.

On average Blacks are more aggressive than Whites, and Whites more so than Asians. This is due primarily to differences in testosterone levels."

Are you blind, or did you just decide to ignore dragon horse's response at the top of the page?

His question, which is much more interesting than your parrotting, refers to the fact that populations of northeastern Asia (e.g. Mongols, Koreans, Tungus, etc.) and some indigenous populations of the Americas have the broadest faces of any extant human groups. But do they also have the highest levels of testosterone and aggression?

I think Dragon Horse is on the right track. If you've based a scientific study on the facial structure of hockey players, then you've based a study on the facial structure of white northern Europeans.

It's very doubtful you could extend the findings across other groups.

An interesting anecdotal corollary: I've noticed from watching Ultimate Fighter on TV that the combatants often have a characteristic big, square jaw. This distinct jaw is very noticeable, and is certainly found among these elite fighters at a higher frequency than the general population. But there could be two different reasons. First, this jaw could be an honest signal of some biological process that temperamentally predisposes one to view fighting as a vocation. Or second, this particular kind of jaw is not an honest signal of temperament, but is instead found at a higher frequency among elite fighters because it confers some advantage in the octagon. (Perhaps this kind of jaw is less likely to break? Or is more able to absorb blows without transmitting the kinetic energy directly to the mastoid, and hence the skull, thereby, by some small percentage, preventing the number of knockouts a fighter might face. This in turn would increase both his liklihood of success as a figher and the liklihood that I would see him on TV and make this observation.)

I dont see were you people are drawing your conclusions from. Besides they chose one sport as an example, not that Hockey is the most agressive sport or whatever. Ryan Del Monte, the man the article used, isnt Northern European besides.

"Are you blind, or did you just decide to ignore dragon horse's response at the top of the page?"

Why do I need to address anyone's comments? Unlike you, I don't spend much time reading blogs. I have better things to do.

But to address your concern, yes, Mongoloids (as I understand) have some of the broadest faces on earth, and they are typically less aggressive.

Among Caucasian groups, specifically Northern Europeans (e.g., hockey players), there may be a correlation between facial breadth and aggression. Across racial lines, this correlation probably does not hold.

Sometimes answers aren't as simple as we'd like, but that's no reason to get worked up over a blog post. Anyway, face to face, I doubt you'd talk to me that way. In fact, I bet you probably can't even bench your own weight.

But to address your concern, yes, Mongoloids (as I understand) have some of the broadest faces on earth, and they are typically less aggressive.

The breadth of the face is not what typifies the Mongoloid face; many Caucasoid groups are broader-faced than many Mongoloid ones. Of course some of the most broad-faced groups are found among the Mongoloids, but that isn't what is typical about them.

I don't really know why you think that Mongoloids are typically less aggressive.

"I don't really know why you think that Mongoloids are typically less aggressive."

Politically and militarily, Asians can be very aggressive. This is because their intelligence (and tendencies to adhere to authority) allows them to become a powerful force in large-scale organizations.

Individually, racial variation notwithstanding, Asian men have a very difficult time coming across as manly. Their frames are weaker and they evidently have less testosterone. Psychologically, they are nowhere near Blacks in their socializing with strangers, especially members of the opposite sex. They are more likely than Whites and Blacks to be introverted computer nerds.

Aggressiveness is also a somewhat vague concept. A person can be aggressive on the football field and with women, but not in entrepreneurial activity or hacking. And vice versa.

"I think you are generalizing from anecdotal evidence pertaining mostly to Asians in the Western world."

Yes, I do base my statements largely from many real-world examples. But Rushton's r-K continuum model in "Race, Evolution and Behavior" also supports my views.

Keep in mind that scientists -- oh, aren't their opinions supposed to be trustworthy? -- have a hard time accepting that Blacks have genetic advantages in sprinting (or at least they have a hard time admiting it publicly!).

"Right, and sprinting is the epitome of aggressiveness whereas martial arts aren't.."

I don't see martial arts as "aggressive" per se. Many practitioners see it as a means of self-defense. Surely you are aware of that, Dienekes?

Your intentional misinterpretation of my comment on sprinting aside (ha ha :P), arguing that martial arts is the epitome of aggressiveness is like arguing that rifles and machetes are the epitome of aggressiveness: these are merely tools of combat, although martial arts have a spiritual dimension for some people.

"Or second, this particular kind of jaw is not an honest signal of temperament, but is instead found at a higher frequency among elite fighters because it confers some advantage in the octagon. (Perhaps this kind of jaw is less likely to break? Or is more able to absorb blows without transmitting the kinetic energy directly to the mastoid, and hence the skull, thereby, by some small percentage, preventing the number of knockouts a fighter might face. This in turn would increase both his liklihood of success as a figher and the liklihood that I would see him on TV and make this observation.)"

There's also the simple fact that at low body fat % levels the jaw appears much more striking and angular. This is actually a surprisingly dramatic variable.

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